Looper mechanism for sewing machines



Nov. 28, 1967 J. N. COVERT LOOPER MECHANISM FOR SEWING MACHINES 4 Sheets-Sheet 1 Filed June 30, 1965 Nov. 28, I967 J. N. COVERT 3,354,851

LOOPER MECHANISM FOR SEWING MACHINES Filed June 30, 1965 4 Sheets-Sheet 2 Nov. 28, 1967 J. N. covER'r 3,354,851

LOOPER MECHANISM FOR SEWING MACHINES Filed June 30, 1965 4 Sheets-Sheet 5 Nov. 28, 1967 J. N. covE l'-. 5 v

LOOPER MECHANISM FOR SEWING MACHINES Filed June 30, 1965 4 Sheets-Sheet 4 FIGJO. F|G.l I.

United States Patent 3,354,851 LOOPER MECHANISM FOR SEWING MACHINES John N. Covert, Lombard, Ill., assignor to Union Special Machine Company, Chicago, IiL, a corporation of Illinois Filed June so, 1965, Ser. No. 468,462 13 Claims. (Cl. 112-200) ABSTRACT OF THE DISCLOSURE A sewing machine construction embodying on and within its frame conventional work feeding mechanism, at least one reciprocatory needle, at least one four-motion looper cooperating with said needle, a main drive shaft and connections from the latter for operating the work feeding mechanism, the needle and the four-motion looper. The connections mentioned are adapted to impart 100p seizing and shedding movements to the looper or loopers and also needle avoid movements to the looper or loopers. Such connections include a reciprocatory and oscillatory rod extending transversely of the direction of feed imparted by the work feeding mechanism, said rod having the looper or loopers releasably connected thereto and being adapted upon reciprocatory movements to provide the loop seizing and shedding actions mentioned. The oscillatory movements of said rod serve to provide the needle avoid movements mentioned. Means readily operable by the operator are provided for disconnecting the looper means from the rod to enable free bodily movement of the looper means longitudinally of the rod and thus dispose the looper or loopers in a readily accessible position for rethreading or the like.

This invention relates to a high speed sewing machine for industrial use adapted to form a plurality of lines of two-thread chainstitches by the cooperation of vertition of the machine a separate looper cooperates with each of the needles to produce a line of two-thread chainstitches. Such stitches are formed by the cooperating of a four-motion looper with a reciprocatory needle, the looper being given loop seizing movements into the loop of thread provided by the needle as the latter is just being retracted or moved upwardly. Then a transverse or needle avoid movement is imparted to the looper after the needle has been retracted. Next the needle is returned downwardly through the work and the loop of thread carried by the looper. A return movement away from the needle is then imparted to the looper and as the latter is in its most retracted position a reverse transverse movement is also imparted to the looper to enable it to repeat the same movements for the next stitch.

In accordance with the present invention each of a plurality of loopers is given a straight longitudinal movement for seizing the thread of a cooperating needle and a reverse movement for shedding said thread, and at the appropriate times in each cycle it is given a needle avoid movement first in one direction and then the other by rocking the longitudinally reciprocatory rod to which the loopers are secured.

An important feature of the invention is the provision of manually operable means, readily accessible to the operator, for simply and quickly disengaging certain means for connecting the loopers to the looper rod for reciprocation with the latter. This enables the loopers to be manually shifted along the rod into a readily accessible position for rethreading or the like, whenever desired.

3,354,851 Patented Nov. 28, 1967 A further feature of the invention is that the frame structure and mechanism employed in the vertically extending and overhanging portion of the frame may be identical with that employed in a lockstitch machine of the character disclosed in the patent to Covert No. 2,977,910, granted Apr. 4, 1964. The base portion of the frame of such a machine is then simply modified to substitute the looper mechanism of the present machine for the rotary hook construction of said patent. This makes possible the assembly and storage of a suitable supply of upper frame structures and of alternatively usuable base structures to meet the demands for lockstitch machines and two-thread chainstitch machines, if the frame structure is so devised as to provide separate units for the base, on the one hand, and a vertical standard and overhanging arm, on the other hand.

Even if the frame structure is not so devised as to form separate entities of the base and upper structures of the frame, various advantages are achieved by having the difference between lockstitch and two-thread chainstitch machines only in the base of such machines. For example, replacement or repair parts for the mechanism in the upper structure will be the same, thus minimizing the amount of storage of such parts.

Certain of the features described above may be used advantageously in machines having only a single needle and a single looper.

Other novel features with resulting advantages will be pointed out hereinafter in the detailed description of the preferred embodiment of the invention.

The preferred embodiment of the invention will now be described in detail by reference to the accompanying drawings in which:

FIG. 1 is a plan view of the base portion of the frame of the sewing machine, with certain parts broken away and others shown in horizontal section;

FIG. 2 is a vertical sectional view of certain parts taken along the line 2-2 of FIG. 1;

FIG. 3 is a rear elevational view of the two loopers and their supporting means;

FIG. 4 is a front elevational view of the two loopers and their supporting means, taken along the line 4-4 of FIG. 1, and shows their relationship to the needles;

FIG. 5 is a view similar to FIG. 4 showing the looper carrying means released from the supporting shaft and shifted toward the 'right in relation to the latter;

FIG. 6 is a plan view of the loopers, their supporting means and the rod or shaft which carries the same;

FIG. 7 is a front elevational view of the looper mechanism shown in FIG. 6;

FIG. 8 is a rear view of a needle guard rocker assembly embodied in the base of the machine;

FIG. 9 is a side elevational view of the needle guard assembly showing it in relation to the main drive shaft of the machine;

FIG. 10 is a detail view in elevation of a member embodied in the looper assembly;

FIG. 11 is a side view of the member shown in FIG. 10;

FIG. 12 is a side view of a counterweight. which is applied to the drive shaft in the base of the machine;

FIG. 13 is a perspective view of a clamp plug provided on the looper carrying and operating rod or shaft;

FIG. 14 is a side view, with certain parts shown in vertical section, of the driving connection from the main drive shaft to the means for shifting the looper carrying rod or shaft longitudinally;

FIG. 15 is a perspective view of a bracket applied to the right end of the assembly shown in FIG. 14;

FIG. 16 is a vertical sectional view through the member which guides the looper carrying rod or shaft and enables the rocking of the latter, the looper carrying rod or shaft being shown partly in elevation and partly in section;

FIG. 17 is a cross-sectional view taken along the line 1l717 of FIG. 16;

FIG. 18 is a perspective view of a member connected with the looper carrying rod or shaft;

FIG. 19 is a perspective view of the left end portion of the looper carrying rod or shaft, and

FIG. 20 is a side. view of a screw element for retaining certain parts assembled on the looper carrying rod.

As shown in the above-mentioned Covert patent, the machine comprises a frame having a base portion, "a vertically extending standard and an overhanging arm. The

latter 'has 'a main drive shaft journalled therein and extending longitudinally of the same. The right end of said shaft, as viewed in FIG. 1 of said Covert patent, carries a combined handwheel and pulley by which the shaft may be rotated, either by manual turning of the handwheel or by 'a suitable connection of the pulley with a motor or electric transmitter. The mechanism disclosed in said patent may be provided in the overhanging arm for reciprocating a needle bar and performing other functions. Connections are provided from said shaft for driving a shaft in the base of the frame for operating the looper and other mechanisms provided therein. Such connections include a toothed pulley secured to said main drive shaft which is connected by a toothed or ribbed belt (FIG. 1) with a toothed pulley 11 on a drive shaft 12 extending longitudinally of the base 13 of the frame of the machine. This arrangement is such that the main drive shaft in the upper arm of the machine and the drive shaft 12 in the base of the machine are rotated in unison at the same speed. Shaft 12 is formed of three interconne'cted sections which are suitably journalled 'in bushings 14, 15, 16 and 17 mounted in the baseo'f the frame. A hub 11a of the pulley 11 -is secured by a set-screw 11b to one end .of'the shaft 12 and cooperates with the right end of bushing 14, while a collar 18'is secured by a setscrew 18a to theshaft 12, inwardly of the bushing 14, to retain the shaft against longitudinal movement toward the right (FIG. 1). Connections of conventional character are provided from the left-hand end or section of theshaft '12 for operating the feed mechanism of the machine. Mechanism of the character disclosed in the patent to Hayes No. 2,973,732 granted Mar. 7, 1961, may be employed for the purpose. Briefly'it comprises a feed bar'19 (FIG. 1) which carries a feed'dog at its forward end. The rear end of the feed bar is rockably connected with a feed rocker 20 which has connected therewith an arm 21 which extends forwardly and cooperates with an eccentric 22 secured to the main drive shaft 12. It will be understood that a pitman cooperating with the eccentric is connected with the forward end of the arm 21 to cause rocking of the feed rocker 20 and impart feed and return movements to the feed dog. For lifting and lowering the feed dog into and out of engagement with the work that is being held downwardly by a presser foot, suitable connections of a conventional type are provided from another eccentric on the main shaft 12 to a downwardly extending arm of the feed bar 19. This constructiton may also be of the character illustrated in the above-mentioned Hayes patent.

The stitch forming mechanism of the machine involves a reciprocatory needle bar in the head of the overhanging arm of the frame and which is operated in the manner shown in the above-mentioned Covert Patent 2,977,- 910. The lower end of the needle bar carries a pair of needles indicated in cross-section by the dots 23 and 23a in FIG. 1 hereof and in their down position in relation to the loopers in FIGS. 4 and 7. Cooperating with the needles are two looper elements 24 and 25. One of these cooperates with one of the needles and the other cooperates with the other needle.

Turning now to FIGS. 3 and 4, it will be seen that the loopers 24 and 25 are mounted on a carrier block or holder 26 mounted on a looper rod 27. Holder 26 has two upwardly extending lugs 28 disposed laterally and longitudinally in relation to each other on the holder, each of these lugs being provided with an opening to receive the shank 29 of the associated looper. Set-screws 30 are provided for firmly retaining the shanks of the loopers within the openings mentioned.

The rod 27 has a solid portion 27a toward its right end (FIG. 16) and a hollow portion 27b toward its left end. The rod is mounted for sliding movement in a hearing sleeve 31 having reduced extensions 31a and 31b at its ends, these extensions being journallecl in bushings 32 carried by the frame structure at the base of the machine. As will be explained, the bearing sleeve 31 is capable of slight rocking movement to impart needle avoid move ments to the loopers carried by the rod 27. For maintain ing the rod in a definite rotational position in relation to the sleeve 31 the latter is provided with a longitudinally extending keyway 310 with which cooperates the head of a stud 31d having a shank portion 31efitted into an opening in the solid portion 27a of the rod. For retaining the key element firmly fixed to the rod 27 there is provided an element 33 having an arcuate groove at one end 'for engaging the surface of shank 31c (FIGS. 13 and 16). A set-screw 34 serves to'urge the element 33 firmly against the stem or shank 31c of the key element. The hollow portion 27b of the rod 27 is provided with a groove 270 in its outer surface (see also FIG. 3) with which cooperates the inner end of a screw element 35 threaded into the holder 26. This serves'to-prevent rotation of the holder about the rod 27 but it permits relative movement of these parts in a longitudinal direction. Hollow portion 27b of rod 27 is also provided with 'a'transversely extending groove 27d in its outer surface, this groove being disposed at a slight angle to a plane perpendicular to the axis of the rod 27. Cooperating with the groove 27d is an extension '36 '(FIGS. 10 and 11) of a block 37 secured to a vertically slidable locking and releasing member 38. The upper'end of this member has a laterally extending portion 38a which is readily accessible to enabledepressing the member 38 by 'the finger of the operator when= ever desired for'the purposes to be hereinafter described. Member 38 is slidable in a groove "provided on the inner surface of a small plate '38bsecured'to the outer face of carrier 26 by screws 380. The left end of rod '27 (see FIGS. 16 and 19) 'is provided with a right angular opening 27e'through its wall, and diametrically opposite this opening is 'afurther opening 27] of similar form. This 'is' not actually needed but simplifies the milling of'slot 276i Theopening 27e'is'provided'to cooperate with extension 39aof an element 39 (FIG. 18). Similarly one of the side walls'of carrier 26 is provided with a groove or slot 26a=(FIG. 3) to receive the extension 39a with a loose fit andthe'oppositewall of the carrier is provided with 'a' slot 26b (FIG. "4) to'receive'extension 3911 with a tight fit that insures againstrelative turning of the=rod 27 and the block or carrier 26. Element 39 is secured to the left end of the rod '27 by means of a screw 40 (FIG. 20) 'having a threadedstem portion cooperating with internal threads 27g at the leftend of the rod 27. screw 40 has a slightly enlarged head with a slot extending across its outer face adapted to receive a screw driver for the assembly of the parts. The head portion of screw 40 cooperates With theouter face of element 39'to'firnily retain the latter fastened to the left end of rod 27. When the parts are assembled, as shown in FIG. 4, the sloping surfaces of theprojection 39b are held firmly in engagement with the-sloping surfaces of the opening 27 Whenthe locking and releasing slide member 38 is in its normal position, as shown in 'FIG.'4,-the projection 36 of plate37cooperates with the transverse groove 27d in the rod'to retain the holder 26 in a definite position in relation to the rod 27. A spring 41 mounted by a screw 42 to a downward extension of the holder 26 normally urges the locking and releasing member 38 upwardly into its active position. However when the operator wishes to shift the loopers 24 and 25 into a more accessible position for threading purposes or the like, the member 38 will be depressed by the finger of the operator and this will enable the operator to shift the holder 26 axially along the rod 27, toward the left in FIG. 3 or toward the right in FIG. 4. Such shifting of the holder will bring it into the position shown in FIG. 5. When the holder is in such position the loopers are quite accessible for threading purposes.

For imparting the longitudinal movement to the looper rod 27, to give loop seizing and shedding movements to the loopers 24 and 25, there is provided a pitman 43, shown in detail in FIG. 14. This pitman has a head portion, including a removable block 43a secured by screws 43b to the body of the pitman and arranged to cooperate with a ball crank 12a carried by the mid-section of the drive shaft 12. Between the heads of the screws 43b and the outer face of the block 43a there is provided a member 43c, shown in detail in FIG. 15. The latter has an extension 43d at right angles to the end portion thereof and this extension has guide surfaces 432 which cooperate with a cylindrical portion 12b at one side of the ball crank 12a. This insures proper longitudinal movement of the pitman 43 by the ball crank. Upon rotation of the latter the ball crank 12a will reciprocate the pitman 43 and its forward end FIG. 1 cooperates with a ball extension 44 of an arm 45 of a bell crank lever rockably supported by the frame of the machine. This lever has another arm 45a. The end of the pitman cooperating with the ball extension 44 is in part provided by a block 43 secured by screws 43g to the left end (FIG. 14) of the pitman. A large opening 43h is provided in the central portion of the pitman to provide for the passage therethrough of the right end of the rod 27 (FIG. 1).

The arm 45a of the bell crank has its outer end divided to provide two extensions 45]; arranged to str-adle a reduced diameter portion at the right end of the rod 27 (FIG. 1). These two extensions of arm 45a rather snugly receive the reduced diameter portion of the rod and they are disposed between two hard steel washers 47, the right hand one of which is urged against a clamping element 46 secured to the end of the rod. The left hand washer 47 is held against a flange 43 integral with or otherwise secured to the rod 27. It will be seen from this arrangement that rocking of the bell crank through the operation of the pitman 43 will serve to shift the rod 27 back and forth in a longitudinal direction.

For rocking the bearing sleeve 31, and hence also the rod 27 to impart needle avoid movements to the two loopers, there is secured to the drive shaft 12 an eccentric 49 (FIG. 2). This is surrounded by a needle bearing unit 50 which is in turn surrounded by a cylindrical portion 51 of a pitman (see FIG. 2). The lower end of the pitman is connected by a bolt 52 with an arm 53 that is clamped to the bearing sleeve 31 adjacent the bushing 32 (FIG. 1). Thus it will be seen that upon each revolution of the drive shaft 12 the bearing sleeve 31, and hence the rod 27, will be rocked back and forth to an extent sufiicient to impart the desired needle avoid movements to the loopers at the appropriate time in their longitudinal loop seizing and shedding movements.

A needle guard member is provided for insuring proper downward movement and alinement of the needles to properly position them in relation to the loopers and also prevent breakage of the needles by engagement with a strictly flat surface. It has been found necessary or desirable to have the needle guard member mounted independently of the looper mechanism but shifted toward and away from the path of the needles at appropriate times in a cycle of operation of the machine so that they will not interfere with the longitudinal movement of the loopers when the needles are down. This mechanism is shown in FIGS. 1, 8 and 9. It comprises a needle guard element 54 having guide fingers 54a having surfaces which cooperate with the needles as they move downwardly through the Work. The needle guard member 54 is adjustably secured to a longitudinally movable carrier 55 to enable the proper positioning of the guide fingers 54a at the appropriate time in a cycle of operation of the machine. This is accomplished by pivotally connecting the needle guard by means of a stud 54b to the carrier 55 and adjusting screw 54c for slightly lowering or elevating the fingers 54a and a bolt or screw 54d for clamping the parts in adjusted position. Carrier 55 has a forked extension 55a cooperating with the drive shaft 12. A screw 55b enables the adjustment of the distance between the surfaces of the fork to cooperate properly with the periphery of the shaft 12.. At its left end (FIG. 9) the carrier 55 is pivotally mounted by a stud 56 on a rock arm 57. Set-screws 58 serve to retain the stud in the desired position. Rock arm 57 is pivotally mounted on a stud 59 carried by the frame of the machine. An eccentric 60 secured to the drive shaft 12 cooperates with the strap portion of a pitman 61, the other end of which is connected with the stud 56. Through this connection the arm 57 is rocked back and forth upon each revolution of the main shaft and thus imparts the movements discussed above to the needle guard 54 and its needle guiding and deflecting surfaces 54a. Stud 59 is held in fixed position in the frame by means of a setscrew 62 and the rock arm 57 is retained in proper position on stud 59 by a collar 63 secured by set-screws 64 to the outer end of the stud 59.

In FIG. 12 there is shown a counterweight element 65, two of which are preferably employed in the machine to counterbalance certain parts connected with the drive shaft 12. These counterweights, as shown in FIG. 1 may suitably be secured to coupling members 66 which serve to connect the crank portion of the drive shaft with the left and right end portions of the drive shaft.

While the preferred embodiment of the invention has been described in considerable detail, it will be understood that various modifications of certain features of the construction may be made, and that certain novel aspects of the invention may be used to advantage in machines of a somewhat different type. What are believed to be the patentably novel features of the machine are defined by the appended claims.

What is claimed is:

1. In a sewing machine having a frame, said frame carrying work feeding mechanism, a reciprocatory needle, a four motion looper cooperating with said needle, a drive shaft, and connections from said drive shaft for imparting loop seizing and shedding movements and needle avoid movements to said looper, the combination which comprises a nod extending transversely of the direction of feed imparted by said work feeding mechanism and having said looper releasably connected thereto, said rod being mounted in said frame for reciprocatory and oscillatory movements to provide respectively, said loop seizing and shedding and said needle avoid movements to said looper, said connections from said drive shaft serving to impart said reciprocatory and oscillatory movements to said rod, and means readily operable by the operator for partially disconnecting said looper from said rod to enable free bodily movement of said looper longitudinally of said rod.

2. In a sewing machine as set forth in claim 1, means for preventing rotational movement of said looper rela tive to said rod.

3. In a sewing machine as set forth in claim 1, a looper carrying member, said looper being secured to said mem her, said means readily engageable by a finger of the operator being mounted on said carrier member for sliding movement relative thereto in a direction transverse tothe axis of said rod.

4. In a sewing machine as set forth in claim 3, said means readily engageable by a finger of the operator being a Slide mounted for reciprocatory movement on said carrying member.

5. In a sewing machine as set forth in claim 4, said slide and said rod having cooperating means for connecting said carrying member to said rod for longitudinal movement of said member and rod together when said slide is in an operative position but enabling movement of said member relative to said rod when the slide is shifted by a finger of the operator.

6. In a sewing machine as set forth in claim 5, a spring normally urging said slide into its operative position.

7. In a sewing machine as set forth in claim 6, detachable means carried by said rod for retaining said carrying member in a fixed position on said rod when said slide is in its operative position.

8. In a sewing machine having a drive shaft, a plurality of reciprocatory needles and a plurality of four motion loopers, each looper being adapted to cooperate with a different one of said needles for forming a line of twoth-read chainstitches, the combination which comprises a reciprocatory and oscillatory looper carrying rod, a looper carrier mounted on said rod and connected therewith for reciprocation thereby, a plurality of loopers secured to said carrier in different parallel planes, said needles being mounted for reciprocation in different planes each of which is adjacent one of said loopers, connections from said drive shaft for reciprocating said rod to impart loop seizing and shedding movements to said loopers, and separate connections from said drive shaft to said rod for imparting slight rocking movements thereto for imparting needle avoid movements to said carrier in timed relation to the reciprocation thereof, said last mentioned connections comprising an oscillating bearing sleeve surrounding said rod, a keyway in said sleeve, a key secured to said rod and arranged for sliding movement in said keyway, said connections from said drive shaft for imparting rocking movements to said rod comprising an eccentric secured to said shaft, a pitman having a strap portion surrounding said eccentric, an arm secured to said bearing sleeve, and means for pivotally connecting the free end of said arm with the free end of said pitman.

9. In a sewing machine as set forth in claim 8, means operable by a finger of the operator for disconnecting said carrier from said rod to enable relative movement of said carrier and rod in a direction parallel with the axis of said rod.

10. In a sewing machine as set forth in claim 9, said loopers having elongated loop seizing beaks provided with elongated thread receiving openings therein, said loopers being spaced to such an extend in relation to each other in the direction of their loop seizing movement that their thread receiving openings are readily visible and accessible to the operator when said carrier is disconnected from said rod and shifted longitudinally along the same.

11. In a sewing machine as set forth in claim 9, said means operable by a finger of the operator being a longitudinally movable slide member mounted on said carrier.

12. In a sewing machine as set forth in claim 9, means cooperating between said carrier and said rod for preventing relative turning movement thereof regardless of the position of said means operable by a finger of the operator.

13. In a sewing machine as set forth in claim 11, a spring normally urging said slide member into a position to connect said carrier and rod for movement together in the direction of the axis of said rod.

References Cited UNITED STATES PATENTS 1,316,400 9/1919 Tate ll2200 2,211,619 8/ 1940 Hacklander et a1. ll2.--200 2,310,320 2/ 1943 Rubel 112227 PATRICK D. LAWSON, Primary Examiner.

RICHARD J. SCANLAN, JR., Examiner. 

1. IN A SEWING MACHINE HAVING A FRAME, SAID FRAME CARRYING WORK FEEDING MECHANISM, A RECIPROCATORY NEEDLE, A FOUR MOTION LOOPER COOPERATING WITH SAID NEEDLE, A DRIVE SHAFT, AND CONNECTIONS FROM SAID DRIVE SHAFT FOR IMPARTING LOOP SEIZING AND SHEDDING MOVEMENTS AND NEEDLE AVOID MOVEMENTS TO SAID LOOPER, THE COMBINATION WHICH COMPRISES A ROD EXTENDING TRANSVERSELY OF THE DIRECTION OF FEED IMPARTED BY SAID WORK FEEDING MECHANISM AND HAVING SAID LOOPER RELEASABLY CONNECTED THERETO, SAID ROD BEING MOUNTED IN SAID FRAME FOR RECIPROCATORY AND OSCILLATORY MOVEMENTS TO PROVIDE RESPECTIVELY SAID LOOP SEIZING AND SHEDDING AND SAID NEEDLE AVOID MOVEMENTS TO SAID LOOPER, SAID CONNECTIONS FROM SAID DRIVE SHAFT SERVING TO IMPART SAID RECIPROCATORY AND OSCILLATORY MOVEMENTS TO SAID ROD, AND MEANS READILY OPERABLE BY THE OPERATOR FOR PARTIALLY DISCONNECTING SAID LOOPER FROM SAID ROD TO ENABLE FREE BODILY MOVEMENTS OF SAID LOOPER LONGITUDINALLY OF SAID ROD. 